Posted by **Anonymous** on Monday, February 18, 2013 at 10:52am.

You have 800 feet of fencing to enclose a rectangular plot that borders on a river. If you do not fence the side along the river,find the length and width of the plot that will maximize the area. What is the largest area that can be enclosed?

- College Algebra -
**JJ**, Monday, February 18, 2013 at 11:35am
I know how to do this with calculus, but algebraically it starts the same way.

L + 2W = 800 L = 800 - 2w

A = LW

A= (800-2w)w

A = 800w - 2w^2

Take the derivative: 800 -4w

800 -4w = 0 to find max.

800 = 4w

200 =w

l = 400

- College Algebra -
**Anonymous please help :)**, Monday, February 18, 2013 at 11:43am
Thank you!

- College Algebra -
**Yan**, Thursday, August 14, 2014 at 10:17am
How did it become 800-4w from 2400-2w^2?

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